I'll be 2 points short off the cut-off if sibling's points are not considered.
Then I'd strongly suggest you be pro-active, and not wait for them to request anything.
It's a critical element of your application, and should try to protect yourself from uncertainty as much as possible.
Move rocks and mountains to get ahold of your respective birth certificates.
Although there is always a possibility of everything being fine with what you've given them, you can't run the risk of waiting for them to ask for birth certificates, as they'll only give you a very limited amount of time to submit them. You're probably in a situation where it would take you quite some time, so I'd suggest you be pro-active.
It's better to have it and not need it, than need it and not have it...
If they don't ask for anything, awesome! If they do, you'll be ready, and you'll just give them the birth certificates...